docs: def get_parser(segmenter, **options):
    """Gets a parser.
  
    Args:
      segmenter (str): Segmenter to use.
      options (:obj:`dict`, optional): Optional settings.
  
    Returns:
      Parser (:obj:`budou.parser.Parser`)
  
    Raises:
      ValueError: If unsupported segmenter is specified.
    """
    if segmenter == 'nlapi':
      return NLAPIParser(**options)
    elif segmenter == 'mecab':
      return MecabParser()
    elif segmenter == 'tinysegmenter':
      return TinysegmenterParser()
    else:
      raise ValueError('Segmenter {} is not supported.'.format(segmenter))